<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div id="app">{{obj.age}}</div>
  
</body>

<script src="./node_modules/vue/dist/vue.min.js"></script>
<script>
    var vm = new Vue({
        el:'#app',
        data:{
            name:'zhujian',
            obj:{
              
            }
        },
        mounted(){
            console.log('mounted');
        }
    });

    // vm.obj.age = '22';
    // vm.$set(vm.obj,'age',22)
    setTimeout(()=>{
        vm.$set(vm.obj,'age',22)
        // vm.obj.age = '22';
    },2000)
   

   

  

</script>
</html>